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Last week we showed you an educational kit from Zilog showing the process involved in making and assembling a Z80 processor, from polished wafer to packaging. Zilog also made a kit for marketing the various packages used. This kit contains a shrink DIP 64 pin socket, a shrink DIP 64pin package, a 48 pin DIP and 40 pin DIP, all the common packages used at the time.

Zilog Packages – Z8 Z80 Z800 and Z8000

At the time is a little hard to track down as no date is provided with this kit. We can get very close though looking at the back where Zilog lists which devices are available in these packages. The usual Z80 and Z8000 series are both there as well as the Z8 microcontroller family. The one odd-ball is the Zilog Z800. The Z800 was an upgraded Z80 released in 1985, adding on chip cache an MMU and a vastly expanded instruction set (over 2000 instruction/addressing modes). It was wholly unsuccessful partly do to bad marketing by Zilog, and partly because it did more then it needed to. It never entered mass production, and by 1986 Zilog has redesigned it, converted the design to CMOS (from NMOS) and released it as the Z280 which met the same fate as the Z800. It seemed that making an overly complicated Z80 wasn’t what the market wanted. THe Z180 (designed by Hitachi) and the Zilog eZ80 (released in 2001), have enjoyed much wider success, mainly because they kept closer to the simplicity of the original Z80.

So when was this kit put together? Likely 1985, as the Z800 was nly talked about for a few months before quietly being put away.

In 1974 Federico Faggin left Intel after working on the 8-bit 8080 processor. He formed a company called ZiLOG and developed a much improved version of the 8080 called the Z80. It was released in 1976 after only 18 months of design. The Z80 was faster, cheaper, and simpler to build around then the 8080 and enjoyed extremely wide use. ZiLOG designed the CPU but it was marketed differently then most at the time. Any company could purchase a license to the design, and build them royalty free. They were also free to do with the design as they pleased. This resulted in dozens of companies making clones/versions of it. The Soviets made unlicensed copies as well. In fact other companies made more Z80s then ZiLOG did themselves.

Zilog Z-80 CPU 8400X CS - 1979 2.5MHz

The Z80 was not the only processor that ZiLOG made. Some of the processors/part numbering can be a bit confusing so we’ll look at each family and part that Zilog made up through 1985. After 1985 CMOS designs came out as well as dozens of variations. We just want to look at the first ten years of ZiLOG.

Zilog Z8300-3PS - 1984 2.5MHz

The Z80 itself was, of course, similar to the 8080 but single voltage, and only required a single clock phase. It was available in speeds of 2.5-8MHz. ZiLOG also made a low-power version known as the Z80L (Z8300) that ran from 1-2.5MHz. That’s really all there was to the Z80 family up through 1985.

The Largest CPU Museum!

In my daily hunt for new processors, and other chips for the museum, as well as information about new chips, I constantly come across interesting chips, in strange locations. Here you will get a chance to learn WHERE many of the chips in the museum come from and what they are.